Estimating energy consumption by purpose and analyse standby power in non-residential buildings in Japan Takuo Yamaguchi Bizen Green Energy Corporation 39-6 Higashikatakami, Bizen Okayama 705-0022 Japan [email protected] Yumiko Iwafune the Collaborative Research Center for Energy Engineering (CEE) in the Institute of Industrial Science (IIS) at the University of Tokyo 4-6-1 Komaba Meguro-Ku Tokyo 153-8505 Japan [email protected] Keywords energy savings, commercial buildings, audit programme, en- to the actual consumption, and the method can show the en- ergy management system, standby power, estimation ergy consumption of each purpose with a low cost. The study analyses the standby power of two city hall build- ings by using the measured electricity consumption data in Abstract detail. In this study, standby power consumption is defined as The purpose of the study is tosupport energy saving endeav- electricity consumption that is consumed despite a not-work- ors in small and medium-sized non-residential buildings. The ing day. Th e electricity consumption, which is not considered study measures the energy consumption of 18 non-residential to be standby power consumption such as consumption by a buildings (2 banks, 2 City halls, 1 convention hall, 4 elderly computer server and an Emergency Power Supply (EPS), is nursing homes, 2 food plants, 2 school lunch facilities, and 5 carefully removed, but the electricity consumption of vending restaurants) in detail, and develops an estimation method of machines and the emergency exit signs is included. This study their energy consumption by purpose. This study also analyse finds that standby power accounts for a large part of electric- the measured data, and finds that standby power accounts for ity consumption in a non-residential building. The standby a large part of electricity. power accounts for 14 % to 20 % of electricity consumption To achieve energy savings in non-residential buildings es- in a non-residential building. Further analysis is necessary to timating energy consumption by purpose is important since know the actual state of standby power in a non-residential it will allow designers to calculate in how many years high ef- building. ficientwill pay back the investment more correctly. The correct estimates encourage the building owner to renew equipment. Measuring the energy consumption of each purpose is very Introduction expensive, and non-residential building’s owners cannot afford The purpose of this study is to support energy saving in non- to pay for this type of assessment. The estimation method uses residential buildings by estimating the energy consumption for commonly available data, such as monthly energy consump- energy purpose. It is extremely important to understand energy tion, to estimate energy consumption by purpose at a low cost. consumption by purpose in order to develop an energy-saving The study measures theenergy consumption of each purpose, diagnosis. analyses these data, and develops the method. For a residential building, non-intrusive load monitoring The method separates building energy consumption into methods for energy disaggregation (NILM) have been devel- AC, domestic hot water, lighting, cooking, transformer loss, oping. NILM estimates the electricity consumption of indi- and other devices. The difference between the estimated con- vidual appliances by analysing measured values of reactive sumption of each purpose and the measured consumption can power and real power. Batra et al. (2014) mentioned that a be as high as 17 %. The estimated value of each purpose is close large number of applications and continuous variations of ECEEE SUMMER STUDY PROCEEDINGS 1207 5-373-17 YAMAGUCHI, IWAFUNE 5. BUILDINGS AND CONSTRUCTION TECHNOLOGIES AND SYSTEMS electricity consumption by VFD and HVAC systems ‘increase fluctuations is domestic hot water. The year-round demands the complexity of energy disaggregation in commercial set- with little seasonal fluctuation are lighting, cooking, transform- tings’. It is thusly considered difficult to apply NILM to com- er loss, and other devices. mercial buildings. This study develops the method of estimating the energy There are many energy simulation programs such as TRN- consumption for purpose by using data that is relatively easy to SYS, Energy plus, and CIBSE TM22. Based on the input condi- obtain, such as monthly utility bills. There are two well-known tions, these programs simulate the energy use of buildings and methods for estimating energy consumption by purpose with- estimate energy consumption by purpose. CIBSE TM22 is an out detailed energy measurement. One method is the rated energy diagnostic program created by the Chartered Institu- energy method. It estimates the energy consumption by multi- tion of Building Services Engineers (CIBSE) for non-residential plying the rated energy input and the use of time by each equip- buildings. According to this program, ‘much of effort expanded ment. The method is often used for lighting energy estimation. on TM22 aims to produce a reliable electricity end use break- The other method is the baseline method. It assumes that the down’ (Cohen, 2013). smallest monthly energy consumption in a year is the monthly This study does not adopt a simulation method to estimate year-round demand, and the difference between monthly en- energy consumption by purpose; instead, it investigates a ergy consumption and the monthly year-round demand is the method of estimating energy consumption by purpose by us- monthly seasonal demand. The method is often used for AC ing monthly or daily energy consumption data. It then verifies energy estimation. its accuracy by comparing it with measured energy consump- With the rated energy method, it is difficult to estimate the tion data in detail. With this method, the number of purposes seasonal demand and the year-round demand with large sea- that can be estimated is smaller than through simulation, yet it sonal fluctuation.Th e baseline method allows to estimate the is thought to reflect the actual energy consumption of a build- seasonal demand, but it is difficult to estimate the year-round ing. demand. This study develops a new estimation method using This study also analyses standby power consumption in two methods. a non-residential building by using the measured data. The standby power consumption in a non-residential building has been researched little in Japan, and this study reports the results Data of the early stage research. DATA USED FOR THE ESTIMATION METHOD The estimation methodology The data used for the estimation method arelisted below. The data is thought to be obtained relatively easily in Japan. The study aims to estimate the annual energy consumptionfor AC, domestic hot water, lighting, cooking, transformer loss, 1. Statement of monthly electricity, gas, and oil consumption and other devices (see Table 1)1. Table 2 shows the comparison (past one year or more). between the energy purpose estimated in this study and the 2. Every 30-minute electricity consumption (past one year or purpose defined in ISO 12655: 2013. more). The monthly energy consumption trendfor each purpose can be categorized (see Table 1). AC is a seasonal demand and 3. Hourly temperature data from the nearest meteorological is used little in spring and fall. Domestic hot water, lighting, observatory. cooking, transformer loss, and other devices are year-round de- 4. Detailed appliance data, the number of appliances, rated mands. In the year-round demands, there are a purpose with input and rated output of lighting, AC, domestic hot water. large seasonal fluctuations and somepurposes with little sea- sonal fluctuation. The year-round demand with large seasonal 5. Transformer capacity (kVA), load loss, and unload loss. Table 1. Relationship between energy purpose and energy types for the estimation model. Energy purposes Seasonal Seasonal Energy types Remarks demand/year- fluctua- electricity Gas (town Oil (kerosene, round demand tion gas, LPG) A heavy oil) AC Seasonal Large × × × Domestic hot water Year-round Large × Estimating only Heat source Lighting Year-round Little × × × Cooking Year-round Little × Estimating only gas use Other devices Year-round Little × Including home appliances, motor, electricity use in cooking and so on Transformer loss Year-round Little × Mainly transformer loss 1208 ECEEE 2017 SUMMER STUDY – CONSUMPTION, EFFICIENCY & LIMITS 5. BUILDINGS AND CONSTRUCTION TECHNOLOGIES AND SYSTEMS 5-373-17 YAMAGUCHI, IWAFUNE Table 2. The comparison between the energy purpose in this study and the purpose in ISO 12655: 2013. ISO 12655:2013 This study Space heating AC Space cooling AC Domestic hot water Domestic hot water Air movement AC Lighting Lighting Household/office appliances Other devices Indoor transportation Other devices Building auxiliary devices Other devices Cooking Cooking Other devices (if heat source of cooking equip- ment is electricity) Cooling storage Other devices Devices in data center Other devices Other devices Other specific functional devices Transformer loss BUILDING MEASUREMENTS DATA in the numbers of days across months. The smallest monthly To establish the estimation method and to confirm the validity day average is the value in May 2015, and it is assumed as the of the estimate, the study has measured energy consumption in baseline. The difference between the monthly day average of detail so that it can be classified for each purpose. Table 3 shows electricity consumption and the baseline is assumed as the AC the total floor area, energy consumption per area, and meas- monthly day average. The annual consumption of AC is esti- ured points of each building. The reason why elderly nursing mated by multiplying the day average by the number of the days homes, food plants, school lunch facilities, and restaurants have of each month and totaling them for 12 months. been selected for the study is that these facilities are considered to have high heat demand. This studyfocus ed on the develop- If AC is used throughout the year ment of estimation methods of energy consumption for domes- In the case that a building uses AC throughout the year, the tic hot water and cooking.